A very niece question Karthik. Actually, electron hole is a conceptual and mathematical opposite of an electron. By this i mean that hole is an imaginary concept which is useful in study of physics, chemistry and electrical engineering. W.r.t. Si & Ge if some energy is supplied to their lattice i.e. 1.1eV in case of Si, some of electrons jump from valence band to conduction band leaving a vacancy in the valence band. This vacancy is termed as a hole. For other atoms i.e. other than semiconductor atoms are defined as cations.
In reality, due to the crystal structure properties, the hole is actually not localized to a single position. Rather, the hole is delocalized and spans an area in the crystal lattice covering many hundreds of unit cells. This is equivalent to the idea that we cannot tell which broken bond corresponds to the 'missing' electron, and is supported by uncertainty theorems from quantum mechanics.
Then in such type of dynamic system we cannot talk about exact mass of hole. It is termed as effective mass here which relates the imaginary force( force on the hole due to electric field according to coulomb's law) on the imaginary hole to the acceleration of that hole. Effective mass is also dependent on direction of movement. If effective mass is larger than electron then it has less mobility under the influence of electric field.
The holes themselves don't actually move, but a neighboring electron can move to fill the hole, leaving a hole at the place it has just come from, and in this way the holes appear to move, and the holes behave as if they were actual positively charged particles.
Material Electron effective mass Hole effective mass
Si (4.2K) 1.08 me 0.56 me
Ge 0.55 me 0.37 me
III-V
Ga,As 0.067 me 0.45 me
In,Sb 0.013 me 0.6 me
II-VI
ZnO 0.19 me 1.21 me
Zn,Se 0.17me 1.44 me
Thus we see that mass of electron and hole are not equal. Even mass of electron is not constant. All these are supported by wave nature of particle and lattice structure. If any doubt again feel free to ask..